An Integrated Cofactor/Co-Product Recycling Cascade for the Biosynthesis of Nylon Monomers from Cycloalkylamines.

We report a highly atom-efficient integrated cofactor/co-product recycling cascade employing cycloalkylamines as multifaceted starting materials for the synthesis of nylon building blocks. Reactions using E. coli whole cells as well as purified enzymes produced excellent conversions ranging from >80 and 95 % into desired ω-amino acids, respectively with varying substrate concentrations. The applicability of this tandem biocatalytic cascade was demonstrated to produce the corresponding lactams by employing engineered biocatalysts. For instance, ϵ-caprolactam, a valuable polymer building block was synthesized with 75 % conversion from 10 mM cyclohexylamine by employing whole-cell biocatalysts. This cascade could be an alternative for bio-based production of ω-amino acids and corresponding lactam compounds.

Enzymatic synthesis of sitagliptin intermediate using a novel ω-transaminase.

Enantiopure ß-amino acids are essential precursors of various pharmaceuticals, agrochemicals and other industrially important chemicals. In this study, we selected sixteen potential ω-Transaminases (ω-TAs) by BLAST and phylogenetic tree analysis. These ω-TAs were cloned, purified and tested for their reactivity for the synthesis of model ß-amino acid (R)-3-amino-4-(2,4,5-triflurophenyl) butanoic acid [3-ATfBA], a key precursor for sitagliptin. In an enzymatic cascade, lipase converted ß-ketoester substrate to ß-keto acid, which was subsequently aminated by the selected ω-TA to its corresponding ß-amino acid. A potent enzyme from Ilumatobacter coccineus (ω-TAIC) was identified for the production of 3-ATfBA. The pH dependency of the product inhibition suggested that lowering the reaction pH to 7.0 can circumvent the inhibition of ω-TAIC by 3-ATfBA and about 92.3% conversion of 100 mM ß-keto ester substrate could be achieved. The applicability of this enzymatic system was further evaluated at the scale of 140 mM, wherein 3-ATfBA was generated with excellent conversion (81.9%) and enantioselectivity (99% ee). Furthermore, ω-TAIC was successfully used for the synthesis of various ß-amino acids from their corresponding ß-keto ester substrates.